Middleton stole his first horse at the age of 14. In 1870, he was convicted of murder and was sentenced to life in prison at the
Huntsville Prison. In 1874, he escaped the prison. He was caught stealing horses in
Iowa. After serving 18 months, he moved to
Sidney, Nebraska, where he shot and killed a soldier, Pvt. James Keith of the
5th Cavalry Regiment, on January 13, 1877, from nearby
Fort Sidney in a bar fight. He was arrested but he escaped as a
lynch mob gathered. was dispatched to capture him. Llewellyn, along with an army from detachment under
George Crook lured him to a meeting with a promise of a pardon from the governor. In a melee, two of Doc's gang were killed and a lawman named Hazen was wounded but Middleton was captured and was taken to
Cheyenne, Wyoming, where he was convicted of
grand larceny and served a prison sentence from September 18, 1879, and was released on June 18, 1883. At the time of his 1879 arrest, it was reported that he had stolen thirty-five horses from William Irving of Cheyenne in 1877. In 1884, he and his third bride moved to
Gordon, Nebraska, where he operated a saloon, and was briefly a deputy sheriff. In 1897, it was reported that he was the City Marshal of
Edgemont, South Dakota. In 1900, he later moved to
Gordon, Nebraska. He had a saloon in both Gordon and
Ardmore, South Dakota, and he also became the town marshal. In 1913, he moved to
Orin Junction, Wyoming, where he opened a saloon. After getting into a knife fight at the bar, he was arrested for dispensing liquor illegally. While in jail, he contracted
erysipelas and died. He is buried in Douglas Park Cemetery in
Douglas, Wyoming. ==Media produced of his life==